Japanese Laid-open Patent Publication No. 2006-230129 discusses a technique of supplying power in a wireless fashion through electromagnetic induction. Japanese Laid-open Patent Publication Nos. 2008-301918 and 2008-160312 discuss a technique of supplying power in a wireless fashion using radio waves. Japanese Laid-open Patent Publication No. 2009-501510 discusses a technique of supplying power through magnetic resonance. Magnetic resonance refers to a physical principle in which magnetic fields are coupled between two resonating coils to transfer energy.